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PROPERTIES OF SEVERAL TYPES OF SALTED YOLK 
AND FUNCTIONALITY IN MAYONNAISE/ 



by 

Lisa J. Harrison 
B.S., Texas Tech University, Lubbock, Texas, 1982 

A MASTER'S THESIS 

submitted in partial fulfillment of the 

requirements for the degree 

MASTER OF SCIENCE 

Food Science 
(Department of Animal Sciences and Industry) 

KANSAS STATE UNIVERSITY 
Manhattan, Kansas 

1984 



Approved by 




ajor Professor 



c. 3 



A11H0H 1,28706 



TABLE OF CONTENTS 

LITERATURE REVIEW 

Introduction 

Emulsions 

Egg yolk and emulsification 

Relative volume of phases 

Emulsifying effect of the mustard 

Method of mixing 

Water hardness 

Viscosity 

MATERIALS AND METHODS 

Yolk preparation 

Emulsifying capacity 

Viscosity 

Mayonnaise preparation and testing 

RESULTS AND DISCUSSION 

Liquid yolk 

Frozen yolk 

Yolk solids 

Mayonnaise microbiology 

REFERENCES 

APPENDIX 



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77 

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INTRODUCTION 

Food emulsions are a significant part of the food industry. Milk, a 
natural oil-in-water emulsion, has long been an important and nutritious part 
of the human diet (Graf and Bauer, 1976). As food scientists discovered and 
studied other natural emulsions, man-made food emulsions began to appear. 
Cake batters (Shepard and Yoell, 1976), ice cream (Berger, 1976), margarine 
(Brown, 1949, Weiss, 1970), and meat products such as sausage and 
frankfurters (Schut, 1976) are just a few examples. Another man-made food 
emulsion, whose production and consumption has grown rapidly, is 
mayonnaise. 

The legends connected with the invention of mayonnaise have been 
described by Robinson (1924). Although there is a divergence of opinion as to 
its origin, mayonnaise has been known for many centuries (Robinson, 1924). 
From 1917 to 1927, economic and industrial changes brought about shifts in 
American dietary habits and mayonnaise became a diet staple involving a 
large scale industry (Epstein, 1937). Finberg (1955) estimated that 
approximately 39 million gallons of mayonnaise and salad dressing were 
produced in 1938. By 1953 that figure had risen to over 100 million gallons. 
In 1983, approximately 175,686,000 gallons of mayonnaise and 62,469,000 
gallons of salad dressing were produced, for a total production of over 238 
million gallons (Preston, 1983). This rise in consumption and production seems 
to be due to a continuing increase in sandwich and salad consumption 
(Finberg, 1955). 

Standards of Identity for mayonnaise define the product as a semi-solid 
emulsion made of egg yolk, edible vegetable oil, and acetic or citric acid. It 



2 
also may contain salt, spices or spice oils, natural sweeteners, and various 
natural flavoring ingredients. Oil content must be not less than 65% by 
weight and the product must contain at least 2.5% acetic acid by weight. 
Citric acid in the form of lemon or lime juice may replace the acetic acid at 
a minimum level of 2.5%. The egg yolk may be from separated yolk or whole 
egg, and may be in the liquid, frozen, and/or dried forms. This ingredient 
provides emulsifying properties and gives the mayonnaise a pale yellow color, 
which may not be intensified by any other ingredient. 

EMULSIONS 
Many incomplete definitions of emulsions have been compiled by Becher 
(1957), who also gave his own, more technical definition. Simply stated, an 
emulsion is "a two-phase system of immiscible liquids" (Lynch and Griffin, 
197*) that "posses(es) a minimal stability" (Becher, 1957). One phase is in the 
form of finely divided droplets whose diameters generally are larger than 
O.lu (Becher, 1957). This dispersed, internal, or discontinuous phase is 
suspended in the continuous or external phase. Emulsion stability is increased 
by the addition of an emulsifier, which lowers the interfacial tension. The 
lipophilic (oil loving) portion of an emulsifier orients itself with the oil phase 
of an emulsion, while the hydrophilic (water loving) portion orients with the 
water phase, forming a shell around the droplets of the dispersed phase 
(Figure 1). By orienting itself at the interface, the emulsifier prevents the 
dispersed particles from coalescing and separating out, thereby increasing 
the emulsion's stability (Lynch and Griffin, 197*). The technical aspects and 
mechanisms of emulsions can be found in the abundant literature (Clayton, 
1928, Clayton and Morse, 1939, King, 19*1, Becher, 1957). 



FIGURE 1. Orientation of an emulsifier around the droplets 
in an emulsion. 



5 

Emulsion properties 

Emulsion properties may be physical or chemical in nature, or both. 
Although it is difficult to characterize all facets of emulsions, their 
properties generally depend on the properties of the continuous phase and 
the proportion of the continuous phase to the dispersed phase (Lynch and 
Griffin, 1974). According to Lynch and Griffin (197*) and Bennett (19*7) the 
eight major properties of an emulsion are: 

Appearance. The ingredients used, their color and the difference in 
refractive index, and the particle size of the dispersed phase all influence 
the appearance of an emulsion. A particle size of 0.5 to 5u yields an opaque 
emulsion. Emulsion color usually depends on the color of the continuous 
phase. 

Dispersability and Emulsion Type. Oil-in-water emulsions can be 
dispersed in and diluted by water, while water-in-oil emulsions can be 
dispersed in and diluted by oils. 

Viscosity. Emulsion viscosity depends largely on the viscosity of the 
external phase and the ratio of external to internal phases. In low 
internal-phase-ratio emulsions, such as milk, viscosity is similar to that of 
the external phase. As the concentration of the internal phase increases, 
viscosity also increases. When the volume of the internal phase becomes 
greater than that of the external phase, a high internal-phase-ratio emulsion, 
such as mayonnaise, is formed. Theoretically, only 7*% of an emulsion's 
total volume can be occupied by the dispersed phase when the droplets are 
spherical. However, high internal-phase-ratio emulsions have more than 7*% 
of the emulsion in the dispersed phase, causing distortion of the dispersed 
droplets. This distortion results in a higher degree of plasticity, as well as 



6 
allowing particle size and charge to have a greater effect on emulsion 
viscosity. 

Particle size . The diameter of the internal phase globules usually is 
taken as the particle size. Fine emulsions contain particles with small 
diameters, while coarse emulsions contain large globules. Good stability 
generally is associated with fine, uniform particle size. The type and 
quantity of emulsifier, the order of addition of ingredients, and the amount 
of work done to form the emulsion all influence particle size. 

Particle charge. A charge is present on the dispersed particles of 
almost all emulsions. This charge is extremely important in maintaining 
stability of small particle size emulsions, but is less important in high 
viscosity emulsions, such as mayonnaise. 

Conductivity . Oil-in-water emulsions are strong electrical conductors, 
while water-in-oil emulsions are poor conductors. This property provides one 
means of identifying emulsion types. 

pH. The effects of pH on emulsion stability only recently have begun to 
receive research attention. Changes in emulsions often can be achieved by 
pH adjustments. 

Stability. The stability of an emulsion refers to how long the internal 
phase will stay dispersed under normal conditions of shipping and storage. 
When the droplets of the dispersed phase coalesce and the phases separate, 
the emulsion is referred to as "broken". The rate at which coalescence 
occurs depends on the type and concentration of the emulsifier, the size of 
the dispersed droplets, the charge on the particles, the emulsion viscosity, 
and the transportation and storage conditions to which the emulsion is 
subjected. 



Hydrophile-lipophile balance 

The hydrophile-lipophile balance (HLB) is probably the most common 
means of choosing an emulsifier. HLB is "an expression of the relative 
simultaneous attraction of an emulsifier ...for the two phases of the emulsion 
system being considered" (Lynch and Griffin, 1974). The chemical composition 
and the extent of ionization of an emulsifier apparently determine it's HLB 
value. These values range from 1 to 20. 

In general, emulsifiers with HLB numbers below 9 are lipophilic and 
tend to form water-in-oil emulsions; those with HLB numbers of 11 to 20 are 
hydrophilic and tend to form oil-in-water emulsions. Those with HLB values 
of 9 to 11 are classified as intermediate (Lynch and Griffin, 1974). The type 
of oil to be used also is influenced by the HLB value. Emulsifiers with HLB 
numbers of 7 to 12 are necessary to form oil-in-water emulsions with corn or 
soybean oils, while one with an HLB number of about 5 is required to form 
an oil-in-water emulsion with cottonseed oil (Powrie and Tung, 1976). 

A combination of two or more emulsifiers with different HLB values 
often is necessary to form a stable emulsion (Powrie and Tung, 1976). 
Stability at a given HLB value varies with the emulsifiers used. The HLB 
values of emulsifier combinations can be found by multiplying the weight 
proportion of each emulsifier by it's HLB value and then adding the resulting 
numbers. 

Emulsion types 

Emulsion systems can be divided into two categories (Lynch and Griffin, 
1974): 



1. Those consisting of droplets of oil dispersed throughout an aqueous 
medium are usually referred to as oil-in-water (o/w) emulsions. 

2. Those in which droplets of water are dispersed throughout an oil or 
fat medium are termed water-in-oil (w/o) emulsions. 

Most food emulsions, including mayonnaise, are of the o/w type (Lynch 
and Griffin, 197*). Mayonnaise, though, differs from other o/w emulsions 
since large quantities of oil are emulsified in a relatively small amount of 
water. Mayonnaise, therefore, tends to be more unstable than many other 
food emulsions, but many of the problems associated with its manufacture 
can be applied to other products (Corran, 19*3). 

Mayonnaise formulation varies considerably with the processor, as can 
be seen by comparing the commercial formulas given in Table 1 (Corran, 
19*3) and Table 2 (Weiss, 1970). There are a number of factors that 
influence the characteristics of mayonnaise. Corran (19*3) listed these 
factors as: 

1. egg yolk 

2. the relative volume of the phases 

3. the emulsifying effect of the mustard 
*. the method of mixing 

5. the hardness of the water 

6. viscosity 



TABLE 1. Mayonnaise Composition 
(Corran, 1943) 



INGREDIENT 



Oil 75.0 

Salt 1.5 

Egg yolk 8.0 

Mustard 1.0 

Water 3.5 

Vinegar (6% acetic acid) 11.0 



10 
TABLE 2. Mayonnaise Composition 
(Weiss, 1970) 



INGREDIENT WEIGHT % 



Salad oil 77.0-82.0 

Fluid egg yolk 5.3-5.8 

Vinegar (100 gr.) 2.8-4.5 

Salt 1.2-1.8 

Sugar 1.0-2.5 

Mustard flour'* 0.2-0.8 



Oleoresin paprika . 
Garlic, onion, spices 
Water to make 100% 



Egg solids, 43%. May substitute whole or fortified egg, fluid or dry, 
on a total solids basis. 



Spice oils, oleoresins may be substituted. 
Optional where characteristic color is desired. 



II 

EGG YOLK AND EMULSIFICATION 
Egg yolk, itself a natural o/w emulsion (Baldwin, 1977), also is known to 
be an efficient emulsifying agent for other o/w emulsions (Corran, 1943). 
Intended by nature to produce a chick (Stadelman, 1977), the yolk is a 
complex mixture. Although it may vary, yolk generally contains 15.7-16.6% 
protein, 31.8-35.5% lipid, 0.2-1.0% carbohydrate, and 1.1% ash (Powrie, 
1977). 

Egg yolk fractions 

Egg yolk contains about 28.3% phospholipid (largely lecithin) and 5.2% 
cholesterol (Powrie, 1977) for a lecithin/cbolesterol ratio of about 5.4:1. 
Research by Corran and Lewis (1924) showed that lecithin favored an o/w 
emulsion while cholesterol favored the w/o type. Antagonistic effects were 
seen when both substances were present. Inversion of an emulsion occurred 
when the lecithin/cholesterol ratio was 8:1 when both compounds were in the 
aqueous phase, and at the 1:1 to 2:1 ratio when the cholesterol was present 
in the oil phase. 

Sell et al. (1935), using the above results as a base, added both 
cholesterol and lecithin to mayonnaise preparations. The cholesterol had no 
effect on mayonnaise preparation or stability when added in small amounts, 
although the emulsion weakened when four times as much cholesterol as is 
normally present in yolk was added. Lecithin, on the other hand, lowered 
consistency and decreased stability of the mayonnaise in every case tested. 
After further studies, those researchers concluded that the emulsification 
ability of egg yolk is not due to any one compound, but to an unstable 
complex of lecithin and protein which they termed "lecitho-protein". 



12 

Detrimental effects of lecithin on egg yolk emulsification capacity also 
have been described by Yeadon et al. (1958), by Varadarajulu and 
Cunningham (1972a), and by Cunningham (1975), who also found that 2 to ** 
lecithin significantly increased egg yolk viscosity, but decreased yolk 
foaming capacity and significantly decreased sponge cake volume. 

Chapin (1951) found that the water soluble/ether insoluble portion of 
egg yolk, designated as the livetin portion, possessed poor emulsifying 
properties. However, when it was combined with the water insoluble portion, 
designated as the lipoprotein portion, emulsification ability was increased. 
The lipoprotein alone had a slightly higher emulsification capacity than the 
combination product. Phospholipids added to livetin reduced emulsification 
capacity. 

The emulsification ability of yolk was attributed to the lipoprotein and 
livetin fractions by Vincent et al. (1966), who suggested that those fractions 
aided in emulsion formation by reducing surface tension. 

Davey et al. (1969) studied the emulsifying properties of three crude 
egg yolk protein fractions: lipovitellin, livetin, and lipovitellenin. All reduced 
initial emulsion drainage. Lipovitellenin alone increased subsequent drainage, 
but reduced subsequent drainage when combined with either lipovitellin or 
livetin. Combinations of lipovitellin and livetin increased subsequent 
drainage. Optimum emulsion stability occurred when all three protein 
fractions were present. Although freezing the fractions resulted in an 
emulsion less stable than those made from fresh yolk or fresh combined 
fractions, freezing and thawing did not significantly decrease the emulsifying 
ability of any of the fractions or combinations of fractions. 



13 
Varadarajulu and Cunningham (1972b) also studied the emulsifying 
properties of the lipovitellin, lipovitellenin, and livetin fractions of yolk. 
Results showed that none of the fractions, alone or in combinations, were as 
good emulsifiers as fresh yolk. 

Liquid egg yolk 

Several studies determined the effect of the hen's dietary fats on the 
emulsification capacity of egg yolk. Jordan et al. (1962) found that the type 
of fat in the hens' diets produced no significant effect on emulsion 
separation. Pankey and Stadelman (1969) also found no significant differences 
in emulsification capacity of egg yolk from hens fed rations supplemented 
with corn, soybean, olive, safflower, or hydrogenated coconut oils. 

Davey et al. (1969) found that native yolk gave more stable emulsions 
after 60, 90, and 120 minute drainage periods than emulsions made from 
recombined lipovitellin, livetin, and/or lipovitellenin. Fresh yolk and fresh 
recombined fractions yielded more stable emulsions than frozen yolk or 
frozen fractions. 

Varadarajulu and Cunningham (1972a) found that emulsification capacity 
of liquid yolk decreased as dilution with albumen increased, and suggested 
that this was due to the lower solids content or to interactions between 
albumen proteins and yolk fractions. They recommended that commercial yolk 
manufacturers could improve their products by keeping albumen content 
below 20%. 

Pasteurization did not significantly affect emulsification capacity of 
commercial fresh yolk containing 48 to *9% solids (Varadarajulu and 
Cunningham, 1972b). Homogenization after pasteurization improved emulsion 



14 
stability. Albumen-free yolk heated to 61 °C showed no significant changes in 
emulsion stability, but emulsification capacity was significantly increased by 
heating the yolk to 63°C. 

These same researchers (Varadarajulu and Cunningham, 1972c) studied 
the influence of breed, strain, and age of bird on emulsification capacity. 
Eggs from Brown Leghorns had twice the emulsification capacity of eggs 
from White Leghorns. Emulsification ability of eggs decreased as birds aged. 
Low social dominant strains of both the Rhode Island Red and White Leghorn 
breeds produced eggs with greater emulsification ability than eggs from the 
high social dominant strains. 

Emulsifying properties of pasteurized and stored salted (10% NaCl) 
liquid yolk were studied by Cotterill et al. (1976). In the high 
temperature-short time method, samples were held for 5 minutes at 
temperatures from 62°C to 78°C, while in the low temperature-long time 
method, samples were held at 52°C for 2 to 8 days. Since there were no 
emulsification differences between yolks treated by the two methods, the 
authors concluded that salted yolk could be pasteurized at high temperatures 
without damage to emulsifying properties. 

Frozen egg yolk 

Frozen yolk containing 10% NaCI is the most common form used in 
mayonnaise preparation (Weiss, 1970). The added salt inhibits microbial 
growth during thawing (Weiss, 1970), and reduces the gelation that occurs in 
frozen plain yolk (Powrie et al., 1963, Meyer and Woodburn, 1965). If frozen 
yolk is allowed to thaw evenly, the resulting smooth, heavy paste will be 
about the right consistency for high quality mayonnaise (Kilgore, 1935). 



15 
Studies on the use of frozen-thawed yolk in mayonnaise have produced 
variable results. Kilgore (1935) reported that a higher percentage of frozen 
yolk than of fresh yolk was required to produce a mayonnaise of a given 
viscosity. Miller and Winter (1951), on the other hand, found that frozen yolk 
produced a much stiffer mayonnaise than did fresh yolk. Dilution of the 
thawed yolk was necessary before acceptable mayonnaise could be produced. 
Johnson (1970) also found that frozen yolks produced a stiffer mayonnaise 
than fresh yolks, and sugared frozen yolk produced a stiffer mayonnaise than 
salted frozen yolk. Yolks containing both salt and sugar produced the least 
stable mayonnaise. 

Davey et al. (1969) found that emulsions prepared with fresh yolk were 
more stable than those prepared with frozen yolk. Johnson (1970), on the 
other hand, found that frozen yolk gave more stable emulsions; however, yolk 
containing 5% NaCl gave the most stable emulsions. Several studies, which 
dealt with the influence of freezing on emulsion stability, were conducted at 
about that same time. Jaax and Travnicek (1968) found that emulsion 
separation increased as freezing rate increased when unpasteurized yolk 
containing no additive was used. Method of freezing - either with liquid 
nitrogen or in a household freezer - had no significant effect on stability of 
emulsions made with salted yolks. Palmer et al. (1969a, b) studied the 
influences of pasteurization, freezing, and acidification on emulsification 
capacity of egg yolk. Freezing and storage at either 0°F or -10°F for up to 
four months caused no loss of emulsification ability in either pasteurized or 
unpasteurized salted yolks. Freezing at -20°F for 5 to 6 days followed by 
storage at 0°F resulted in no loss of emulsifying properties, but freezing at 
-20°F and storage at -10°F for 1 to 4 months was detrimental to both 



16 
pasteurized and unpasteurized yolks. Acidification in combination with 
pasteurization, followed by freezing and storage also damaged the 
emulsification ability of salted yolk. 

Yolk solids 

Although yolk solids are used by the mayonnaise industry, few studies 
have been conducted on their functionality in mayonnaise. Several 
investigators, though, have studied the influence of dehydration on yolk 
emulsifying properties. 

Chapin (1951) reported that spray-drying increased yolk emulsification 
capacity; however, vacuum drying decreased emulsifying power. 

Carlin (1955) showed that rehydration of dried yolk with acetic acid 
instead of water apparently decreased its emulsification capacity. Data on 
dried yolks produced from 1949 to 1952 indicated that mayonnaise 
comparable to controls could be produced using 50 grain acetic acid, but 
solids from 1953 produced a similar mayonnaise when either 50 or 100 grain 
vinegar was used. The author concluded that either 50 or 100 grain vinegar 
could be used to produce mayonnaise from yolk solids available at that time. 

Lyophilized yolk was the subject of a study by Rolfes et al. (1955). The 
use of fresh, frozen, and spray-dried samples for comparison indicated that 
lyophilization harmed yolk emulsifying properties. This detrimental effect 
was less when the yolk was diluted before freeze-drying. 

Schultz et al. (1966) reported that drying of yolk resulted in a rapid 
increase in extractability of the "free lipids" which were extremely 
detrimental to the emulsifying capacity of yolk. 



17 
Zabik (1969) studied the emulsification ability of freeze-dried yolks, as 
well as of foam-spray-dried yolks and spray-dried yolks. Frozen yolks were 
used for comparison. Averages of emulsion separation at three pH levels 
indicated that frozen yolks produced the most stable emulsions, followed by 
freeze-dried and foam-spray-dried. Spray-dried yolk produced the least stable 
emulsions. 

Varadarajulu and Cunningham (1972b) also showed that spray -drying was 
detrimental to yolk emulsification ability. Initial separation was significantly 
greater for spray-dried yolk, although emulsion separation at 120 minutes 
was similar for all the samples tested. The authors also reported apparent 
superior emulsification ability with samples processed in a Buflovak drier 
than with yolk dried in a Rogers drier, but the differences were not 
significant. 

Determination of emulsification capacity and stability 
Very few tests have been devised to determine emulsification capacity 
of egg yolk directly. Pankey and Stadelman (1969) added corn oil dropwise to 
a mixture of 0.5 g of whole yolk and 15 ml of distilled water in a 
microblender cup of a Waring blender until emulsion disruption occurred. 
Emulsification capacity was taken as the amount of oil that could be 
incorporated before disruption occurred. Cotterill et al. (1976) used two 
types of phase inversion techniques to determine emulsification capacity. In 
the "monophasic" titration, 10 g of yolk and 81 g of corn oil were mixed 
together in the metal bowl of a Kitchen-Aid mixer to form a w/o emulsion. 
The emulsion then was back-titrated with water to the inversion point, which 
was determined by change in electrical resistance. In the "bi-phasic" 



18 
titration, electrodes on opposite sides of a beaker containing 20 g of yolk 
were used to measure resistance. The o/w emulsion was titrated with oil 
until resistance went rapidly from to 5x10 ohms, which was considered 
the inversion point. An additional 10 ml of oil then was added to convert the 
emulsion to w/o. This emulsion then was back-titrated with water to the 
inversion point, which was at ohms. The amounts of water or oil required 
to reach the inversion points were used as a determination of emulsification 
capacity in all tests. A method similar to that of Pankey and Stadelman 
(1969) was reported recently by Young et al. (1983). In this procedure, 15 g 
of yolk, 20 ml of 0.8M acetic acid, 20 ml of corn oil, and 0.5 g of NaCl were 
mixed in an Osterizer blender at maximum speed. Corn oil was added 
dropwise from a cylinder until the emulsion broke, as determined by a sudden 
drop in viscosity. The total oil (the original 20 ml plus the amount added 
from the cylinder) divided by the weight of yolk used was taken as the 
emulsification capacity. 

Stability of emulsions seems to be a more common way to test 
indirectly yolk emulsification efficiency. Numerous methods have been 
developed to determine stability of both simple emulsions and of mayonnaise. 

Jordan et al. (1962) and Davey et al. (1969) used a method that involved 
blending 15 g of yolk, 15 g of corn oil, and 85 g of deionized water in a 
stainless steel blender cup at 28 to 29°C. After blending 1 minute at 50 
volts and 5 minutes at 110 volts, 15 g portions were transferred to graduated 
15 ml centrifuge tubes and placed in a test tube rack. Emulsion separation 
was recorded after 30, 60, 90, and 120 minutes and was interpreted as an 
indication of stability. 



19 

Variations on the above procedure have been used by several 
researchers. Zabik (1969) adjusted the water content of the formula to allow 
for moisture previously added to the frozen-thawed yolks, increased the 
speed of initial homogenization to 55 volts, and decreased the amount of 
emulsion placed in the centrifuge tubes to 10 mis. Varadarajulu and 
Cunningham (1972a) modified the procedure to use a Virtis homogenizer 
rather than a blender. Emulsion separation was recorded only after 60 and 
120 minutes. 

A procedure similar to that of Varadarajulu and Cunningham (1972a) had 
previously been developed by Jaax and Travnicek (1968). Emulsions consisting 
of 8.5 g of yolk, U.O g of corn oil, and 46 ml of deionized water were 
prepared by blending for 90 seconds in a Virtis homogenizer set at medium 
speed. The formed emulsions were then transferred to 100 ml graduated 
cylinders, and separation was recorded every 30 minutes. Total separation 
was recorded at the end of 3 hours. Johnson (1970) also used this basic 
procedure, but replaced the corn oil with soybean oil and recorded 
separation for * hours. 

Kilgore (1933b) tested mayonnaise stability by shaking a sample of the 
emulsion with an equal weight of water, pouring the solution into a 
graduated cylinder, and allowing it to stand for 2» hours. The amount of 
creaming was used as the measure of stability. 

Stability of mayonnaise often has been determined by simply storing 
samples at room temperature until visible separation occurred. Kilgore 
(1933a) stored samples at room temperature for 1 year before determining 
the amount of separation. Chapin (1951) stored emulsions in a one-half pint 
Mason jar at approximately 21 °C. The length of time required for the first 



20 
appearance of water was taken as the stability measurement. Johnson (1970) 
evaluated the stability of mayonnaise by observing the presence or absence 
of oil separation when samples were stored at room temperature for 2, *, 
and 6 weeks. 

Centrifuging until phase separation occurred was suggested by Bennett 
(19*7) as a test of emulsion stability. Miller and Winter (1951) centrifuged 10 
g samples for 15 minutes and then used the amount of liquid separation as a 
measure of stability. Rolfes et al. (1955) employed an International 
centrifuge at 2000 rpm for 15 minutes to test mayonnaise stability. The 
percent oil separation, determined on a weight basis, was taken as the 
measure of stability. Varadarajulu and Cunningham (1972a) also used an 
International centrifuge, but revised the test conditions to 5000 rpm for 30 
minutes. 

RELATIVE VOLUME OF THE PHASES 
Mark (1921) studied the emulsification of oil in liquid egg yolk by 
taking samples every 10 seconds during emulsion formation and monitoring oil 
dispersion microscopically. Four conclusions were drawn from the data: 

1. If the proportion of egg to oil was kept below a certain maximum, a 
stable emulsion could always be formed regardless of temperature or method 
of beating. 

2. If the amount of oil exceeded a certain minimum, the continuous 
phase became the oil and no permanent emulsion could be formed. 



21 

3. If the proportion of egg to oil was kept between the minimum and 
maximum, formation of a stable emulsion became dependent on variables such 
as temperature and mixing procedure. 

4. If vinegar was used to dilute the egg, the amount of oil that could 
be emulsified permanently increased greatly during initial addition of oil. As 
emulsion viscosity increased, the maximum amount of oil that could be 
emulsified approached the amount emulsified when undiluted egg was used. 

The amount of oil that could be emulsified in a given amount of egg 
yolk was reported by Robinson (1924) to depend on the type of oil being 
used. Amounts of oil that could be emulsified in 15 g of yolk ranged from 
296 g for pure Italian olive oil to 432 g for Wesson oil. The amount of water 
present also was cited as an influence on the amount of oil that could be 
emulsified. 

Gray and Southwick (1929) found that the consistency of mayonnaise 
decreased rapidly as moisture content increased. 

Due to the presence of "free" water, Kilgore (1935) considered fresh 
yolk to be too light in body to produce a good initial emulsion. The author 
reported that some means of holding this excess moisture must be utilized 
with fresh yolk to start the smooth, fine-grained emulsion necessary for high 
quality mayonnaise. 

Corran (1943) reported that the usual procedure in mayonnaise 
production was to emulsify the total amount of oil in a small amount of the 
aqueous phase before addition of the remainder of the. aqueous phase. 
Although the large concentration of oil tended to give rise to a w/o 
emulsion, the emulsifying agents prevented this, and the large amount of oil 



22 
was cited as a major factor in mayonnaise formation. He also reported that 
addition of oil to all of the aqueous phase resulted in an emulsion of very 
low viscosity. 

Lowe (1955) found that 40 g of oil could be emulsified initially in 
approximately 15 g of egg yolk when seasonings and vinegar were added to 
the yolk. These data indicated that mayonnaise formed most readily with a 
small quantity of oil. 

EMULSIFYING EFFECT OF MUSTARD 

In "1932 Kilgore studied the emulsifying effect of mustard on 
mayonnaise. Three tests were used to evaluate mustard: 1) foaming power of 
a mustard/water solution, 2) stability of oil drops on the surface of a 
mustard/water solution, and 3) stability of simple o/w emulsions using a 
solution of mustard and water as the water phase and sole emulsifying agent. 
Results showed that emulsion stability increased as the mustard level 
increased up to 4%. When oil was dropped onto the surface of a 4% solution 
of mustard, the drops stayed completely apart, indicating stabilization due to 
the mustard. In the third experiment, a t t% solution of mustard formed and 
maintained a fairly heavy emulsion. The author concluded that mustard 
exerts a stabilizing effect on emulsions. 

In 1933(a), Kilgore studied the effect of mustard on the permanence and 
consistency of mayonnaise. Mustard was found to have considerable influence 
on the stability of mayonnaise. Consistency of the emulsion was found to be 
influenced greatly by not only the chemical and physical properties of 
mustard, but by the method of incorporating mustard into the mayonnaise. 



23 
After determining the effects of mustard on mayonnaise characteristics, 
Kilgore (1934) reported three methods for testing mustard to be used in 
mayonnaise: moisture holding power, development of flavor, and keeping 
quality. Characteristics of several types of mustard also were described. 

Corran (1943) studied the effect of mustard on oil/lime water mixtures 
that resulted in w/o emulsions when shaken. Data indicated that 2.1% fine 
mustard flour or 2.5% coarse mustard flour caused inversion of the emulsion 
to o/w. Further tests conducted with a mobilometer confirmed that mustard 
confers a measure of stability to mayonnaise. 

METHOD OF MIXING 

Robinson (1924) reported that more oil could be emulsified when 
intermittent mixing was used than when the beating was continuous. Speed of 
oil addition also was cited as a factor influencing mayonnaise production. 

Hall and Dawson (1940) tested two methods of emulsion formation. In 
the American method, the emulsifying agent and acid were combined, 
followed by the gradual addition of oil. In the compromise method, a small 
amount of oil was first added to the emulsifying agent, followed by the 
addition of acid, and then the addition of the remainder of the oil. Each 
method was tested under two conditions - oil was added either from a height 
of 6 inches above the emulsion or was added beneath the emulsion surface. 
Results showed that the introduction of oil beneath the emulsion surface 
improved stability, consistency, and homogeneity of the formed emulsion. The 
authors also found the compromise method to produce emulsions superior to 
those produced by the American method. The best emulsions were produced 



24 
when the compromise method with addition of oil beneath the emulsion 
surface was used. 

Corran (1943) found that the stability and form of emulsions was 
influenced by a number of method-of-mixing factors. Those factors included 
the amount and composition of the aqueous phase added during the first 
stage of mixing, the time of beating, and the degree of agitation. Results of 
tests conducted by that author indicated that, of the various conditions 
tested, a beating time of 5 minutes without initial addition of vinegar 
produced the most viscous mayonnaise. 

Lowe (1955) reported that the kind of bowl used to make mayonnaise 
influenced the emulsion. Placing small quantities of yolk in a large mixer 
bowl was cited as one cause of failure in making mayonnaise. The duration 
of beating and resting periods had a measurable influence on the emulsion. 
The addition of vinegar at various stages in the making of mayonnaise 
affected the consistency of the mayonnaise. 

WATER HARDNESS 
Water hardness was cited by Corran (1943) as a minor factor in 
mayonnaise production. Calcium salts, as well as salts of other divalent 
metals, tend to form w/o emulsions, thereby decreasing mayonnaise stability 
(Corran, 1943, Lowe, 1955). 

VISCOSITY 
Viscosity is an important property of egg yolk to be used for 
mayonnaise manufacture. Numerous studies have been conducted on egg yolk 
viscosity. Chapin (1951) suggested that the "emulsifying index", which was 



25 
based on final emulsion viscosity, was influenced partially by initial 
emulsifier viscosity. Kilgore (1935) stated that frozen-defrosted yolk of good 
quality would be a smooth heavy paste which was about the right consistency 
for mayonnaise. 

According to Payawal et al. (19*6), native yolk containing 49 to 49.5% 
water has a viscosity of approximately 800 centipoises (c.p.s.). Pasteurization 
temperatures above 62.5°C caused a considerable increase in egg yolk 
viscosity. 

Pearce and Lavers (1949) showed that freezing resulted in an 
irreversible increase in egg yolk viscosity. Reduced viscosity was noted in 
defrosted yolk when vigorous mechanical treatment was applied prior to 
freezing. As freezing time increased from 0.2 to 39 hours, a progressive 
increase in viscosity occurred. Viscosity of yolk also was found to increase 
as defrosting time increased from 0.03 to 24 hours. 

The effects of freezing on yolk gelation, which can be considered a 
large increase in viscosity, was studied by Lopez et al. (1954). Colloidal 
milling of the egg yolk prior to freezing inhibited gelation under certain 
conditions. Salt (NaCl) added to yolk before milling, freezing, and frozen 
storage produced yolk with a higher degree of gelation than that with no 
NaCl, while emulsion stabilizers and destabilizers did not inhibit gelation 
either with or without colloidal milling. None of the substances tested, 
including trisodium citrate, trisodium ethylenediaminetetracetate, NaCl, 
sugars, and glycerol, produced a normally flavored yolk and inhibited 
gelation. Sugar, NaCl, and glycerol partially prevented yolk gelation, but 
resulted in marked flavor changes. Quick freezing by immersion in either a 
dry-acetone-ice mixture or in liquid nitrogen partially inhibited gelation. 



26 

Decreased yolk gelation was associated with increased freezing rate, and 
quick freezing combined with rapid defrosting further reduced yolk gelation. 

The effect of salt (NaCl) on yolk viscosity was studied by Jordan and 
Whitlock (1955). Untreated yolk was considerably more viscous than either 
egg white or whole egg magma. As salt levels were increased from 1 to 5%, 
those differences in consistency were found to become increasingly greater. 
Results indicated that the viscosity ratio between the yolk containing 5* 
salt and the untreated yolk was greater than * to 1. 

Marion and Stadelman (1958) also found that the addition of salt 
increased the viscosity of fresh, unfrozen yolk. Gelation was reduced 
significantly by increases in both freezing and defrosting rates. Several 
additives, including hexane, NaCl, and sucrose, were found to effectively 
reduce frozen yolk gelation. 

Powrie et ai. (1963) found that viscosity change in frozen-thawed yolk 
was dependent on the time-temperature relationship of frozen storage. Salt, 
sugar, and cysteine all decreased gelation of frozen yolk. Urea caused a 
definite increase in native yolk viscosity, with a urea level of 0.416 
moles/100 g yolk causing the yolk to gel within 85 minutes. 

Increasing age of eggs resulted in decreased yolk viscosity in studies by 
Meyer and Woodburn (1965). Cysteine- and water-treated unfrozen yolk had 
similar viscosities, while NaCl-treated yolks were more viscous than the 
control. Sucrose caused the most reduction in viscosity. Water was slightly 
less effective than cysteine in inhibiting gelation in frozen-defrosted yolk, 
while NaCl was the most effective in inhibiting gelation in stored 
frozen-defrosted yolk. 



27 

Jaax and Travnicek (1968) found that both NaCl and sugar reduced 
gelation of frozen-defrosted yolk. Yolk frozen in a freezer was more viscous 
than yolk frozen in liquid nitrogen, and liquid nitrogen was less effective in 
retarding gelation in treated yolk than in yolk containing no additive. 

Palmer et al. (1969a, b) found that pasteurization did not change the 
effect of frozen storage on salted yolks, but caused a slightly increased 
viscosity in unfrozen salted yolk. Viscosity of frozen-defrosted yolks stored 
below -10°F increased as shear rate decreased, while unfrozen salted yolk 
viscosity was independent of shear rate. Acidification caused a considerable 
increase in viscosity with pasteurization and frozen storage each 
accentuating that increase. 

Studies conducted by Davey et al. (1969) indicated that the increased 
viscosity of frozen-defrosted yolk could be due to increased viscosity of the 
lipovitellenin fraction as a result of freezing. However, results for this 
constituent were highly variable. 

Scalzo et al. (1970) studied viscosities of 5 commercial egg products. 
They showed that all products, including yolk, produced a linear relationship 
between shear stress and shear rate at temperatures ranging from 5 to 60°C. 
Viscosity of the egg products, therefore, was concluded to be independent of 
shear rate. 

Shear rate also was a factor studied by Chang et al. (1970). Viscosity 
of native yolk with 52.5% solids decreased as shear rate increased. Decreases 
in viscosity of pasteurized yolk with increased shear rate also were noted. 
Thin albumen added at levels up to 20% decreased viscosity of native yolk, 
and increases in yolk viscosity due to heat damage were reduced with 
increasing levels of albumen. 



28 
Palmer et al. (1970) studied the effects of heat treatment after thawing 
on gelation in frozen-defrosted yolk. Temperatures of 45 to 55°C applied for 
1 hour reduced viscosity of white-free yolk and commercial plain, sugared, 
and salted yolks by more than 50%. Temperatures above the 45 to 55°C 
range resulted in protein coagulation and increased yolk viscosity. 

Varadarajulu and Cunningham (1972a, b, c) found that yolk viscosity 
decreased by approximately 80% with the addition of 10% albumen, and by 
about 97% when 25% albumen was added. Pasteurization of commercial yolk 
did not affect viscosity significantly, but pasteurization at 63 to 65°C for 4 
minutes of laboratory prepared yolk produced an increase in viscosity that 
was curvilinear with increasing temperature. Yolk dried in a Buflovak drier 
was significantly less viscous than that dried in a Rogers drier. Although age 
of bird significantly affected yolk viscosity, breed had no effect. 

Cunningham's (1972) study of the viscosity of diluted egg yolk showed 
that yolk with 53% solids had a viscosity of 1600 c.p.s. while yolk with 43% 
solids had a viscosity of only 200 c.p.s. Dilution with water rather than 
albumen produced no significant differences in viscosity. 



29 

MATERIALS AND METHODS 

The infertile eggs used for the fresh liquid and frozen yolk studies were 
collected from caged Leghorn layers housed at the Kansas State University 
Poultry Farm. Eggs were stored in a commercial size walk-in cooler at 4°C + 
1°C for 5 days before being used. Plain dried yolk and free-flow dried yolk 
were obtained from Milton G. Waldbaum Co. (Wakefield, Nebraska). Low 
viscosity dried yolk was obtained from National Egg Products Corp. (Social 
Circle, Georgia). All dried yolk samples were stored in a commercial size 
walk-in freezer at -20°C and were thawed at 4°C +_ 1°C in a commercial size 
walk-in cooler for 2* hours before being used. 

Egg yolk preparation 

Liquid and frozen samples 

Egg components were separated using a household hand separator. The 
yolk was gently rolled on absorbant paper towel to remove adhering albumen 
and positioned near the towel edge. The vitelline membrane was ruptured and 
the yolk liquid collected in 3500 ml plastic jugs. Albumen from the same eggs 
was blended in a Waring blender and approximately 28* (by weight) was 
incorporated into the yolk using a Kitchen Aid mixer, Model K*5SS, (Hobart 
Corp., Troy, Ohio) with a wire whip attachment set at speed 1 for 2 minutes. 
Solids content of the yolk was determined by the overnight atmospheric oven 
method (Gorman, 1977) to verify that the solids content had been reduced to 
the commercially required *3%. 

Liquid yolk samples The diluted yolk was divided into 160 g samples and 
treated with iodized NaCl, uniodized NaCl, or KC1 (No Salt, Norcliff Thayer, 



30 
Inc., Tuckahoe, New York). Each type of salt was added at the 5, 10, and 
15% levels. One sample containing 0% salt was also prepared. A Kitchen Aid 
mixer, Model K45SS, with wire whip attachment was used to incorporate the 
salt. All samples, including the 0% salt, were mixed at speed 1 for 1 minute, 
the beater was stopped and the bowl scraped down, and mixing was then 
resumed at speed 1 for an additional 1.5 minutes. The finished samples were 
stored in 16 oz. plastic screw-top sample jars (Nalgene) at 4°C for not more 
than 24 hours. Samples were allowed to sit at room temperature (27°C + 1°C) 
for at least 1 hour before testing. 

Frozen yolk samples Approximately 1000 ml of prepared yolk was 
weighed into the bowl of the Kitchen Aid mixer. Ten % iodized NaCl was 
incorporated into the yolk by mixing with the wire whip at speed 1 for 1 
minute, stopping the mixer, scraping the bowl, and mixing an additional 1.5 
minutes at speed 1. Fifty g samples of the salted yolk were weighed into 75 
ml screw-top glass sample jars and the jars were capped. The jars were then 
placed in a household type upright freezer at -10°C +_ 2°C. Four jars (200 ml 
total) were stored for each of 30, 60, and 90 days. Four jars were placed in 
the freezer for 2* hours and were then removed and tested. Those samples 
were labeled days frozen storage. Frozen samples were placed in a water 
bath at 37°C + 1°C for 30 minutes, then allowed the stand at room 
temperature (27°C + 1°C) for 20 minutes before testing. 

Dried yolk samples 

Rehydration of the yolk samples was accomplished using a Kitchen Aid 
mixer, Model K45SS, with a wire whip attachment. One hundred and fifty g 
of- dried yolk and 190 g of distilled water were weighed into the bowl. The 



31 
contents were then mixed at speed 1 for 1 minute, the mixer was stopped 
and the bowl scraped, and mixing was resumed at speed 1 for an additional 1 
minute. The weight of rehydrated yolk was determined and 10% iodized NaCl 
was then incorporated by mixing at speed 1 for 1 minute, stopping the mixer 
and scraping the bowl, and then mixing at speed 1 for additional 1.5 minutes. 
The rehydrated, salted yolk samples were placed in 1 qt. Mason jars which 
were kept capped while tests were being conducted. 

Emulsification capacity 

A modification of the procedure described by Young et al. (1983) was 
used to determine emulsification capacity. Fifteen g of salted yolk and 20 ml 
of 5% acetic acid were mixed in an Osterizer blender for 10 seconds at 
speed 12. Twenty ml of soybean oil (Wesson) were added and the mixture 
blended for 20 seconds. More oil was then added dropwise from a 100 ml 
graduated burette until a sudden drop in viscosity occurred, indicating a 
"broken" emulsion. The quotient obtained by dividing the total amount of oil 
(the oil added from the burette plus the original 20 ml) by the g of yolk was 
taken as the emulsification capacity. 

Viscosity 

Viscosity of the salted yolk samples was determined at room 
temperature (27°C + 1°C) with a Brookfield RVF Model Syncro-lectric 
Viscometer. Conditions were spindle 5 and 20 r.p.m. for all liquid yolk 
samples and for the days frozen storage, spindle 7 and 10 r.p.m. for the 
30, 60, and 90 frozen storage, and spindle 7 and 4 r.p.m. for all dried 
samples. Measurements were corrected and reported as centipoise. 



32 



Mayonnaise preparation and testing 

Mayonnaise was prepared using a modification of the formula and 
procedure described by Miller and Winter (1950). The mayonnaise formula 
consisted of: 

Salted egg yolk 16.0 g 

Vinegar (5% acetic acid) 30.0 ml 

Sugar 3.0 g 

Dry mustard (McCormick) 1.0 g 

Soybean oil (Wesson) 237.0 ml 

The yolk, sugar, mustard, and 10 ml of vinegar were mixed for 0.5 
minutes in a Kitchen Aid mixer, Model K45SS, set at speed 8. Forty ml of oil 
were then added from a 100 ml graduated burette over a 6 minute period, 
followed by the addition of 10 ml of vinegar in 0.5 minutes. Mixing was 
continued for 0.5 minutes without the addition of ingredients. The beater 
was shut off, and the mixture was allowed to rest for 1 minute. After 
scraping down the bowl, beating was resumed at speed 8, and the remaining 
197 ml of oil were added from a 500 ml separatory funnel over a 6 minute 
period. The final 10 mi of vinegar were added in 1 minute. After scraping 
down the bowl, the emulsion was mixed on speed 1 for 0.5 minutes. The 
finished mayonnaise was transferred to a i pint Mason jar using a funnel, 
and the jars were capped and allowed to stand at room temperature (27°C + 
1°C) for 20 to 2* hours before testing. 



33 

Apparent mayonnaise viscosity was determined at room temperature 
(27°C +_ 1°C) by a Brookfield RVF Model Syncro-lectric Viscometer (spindle 
7, 4 r.p.m.). Results were corrected and reported in centipoise. Spread of 
mayonnaise was determined by the line spread test described by Grawemeyer 
and Pfund (19*3) and Griswold (1962). In this test, a diagram such as that 
shown in Figure 2 was placed beneath a level glass plate. Each numbered 
circle was separated by 3.175 mm. A metal cylinder (22.225 mm high) with an 
inside diameter of 50.800 mm was placed directly over the smallest circle, 
filled with sample, and leveled off with a spatula. The cylinder was carefully 
lifted off and the mayonnaise was allowed to spread for 2 minutes. After the 
spread period, readings were taken at k widely separated points representing 
the limits reached by the mayonnaise. The average of the 4 readings was 
taken as the number of 3.175 mm units the mayonnaise spread at room 
temperature in 2 minutes. 

Stability of the mayonnaise was determined by incubating the samples 
at *0°C _+ 1°C until the emulsion broke. A broken emulsion was taken as the 
point at which oil became visible at the top of the emulsion, giving the 
mayonnaise a "curdled" appearance. Stability was recorded as the days at 
40°C required for an emulsion to break. 

Standard plate counts (standard plate count agar) were performed 
before and after incubation to determine if a significant increase in bacteria 
occurred. Mold and yeast counts (potato dextrose agar) were also performed 
before and after incubation to determine if a significant increase in mold or 
yeast occurred. 

Data were statistically analyzed by analysis of variance and by 
Duncan's Multiple Range Test. 



34 



FIGURE 2. Diagram of concentric circles used beneath a glass 
plate to measure line spread. 



J5 




36 

RESULTS AND DISCUSSION 

LIQUID YOLK 

Viscosity 

The effects of salt type and level on viscosity of liquid yolk are 
illustrated in Figure 3, while the corresponding treatment means are shown 
in Table 3 (Appendix). 

Salt type was found to have a significant (P>0.05) effect on viscosity of 
liquid yolk. Table 4 (Appendix) shows the viscosity means for each of the 3 
salts. Uniodized NaCl caused the largest increase in viscosity, while KC1 
produced the least increase. Iodized NaCl caused an intermediate increase in 
viscosity. 

Salt level was also found to have a significant (P>0.05) effect on 
viscosity of liquid yolk. Table 5 (Appendix) shows the viscosity means for 
each of the 3 levels. The 5% level produced the least increase in viscosity, 
the 10% level caused an intermediate increase, and the 15% level produced 
the largest viscosity increase. 

The increase in the viscosity of liquid yolk upon the addition of NaCl 
has also been reported by Jordan and Whitlock (1955), Scalzo et al. (1970), 
and Johnson (1970). Jordan and Whitlock (1955) hypothesized that NaCl added 
to yolk tended to cause the lipovitellin to take up water which in turn 
increased the particle size with a consequent increase in apparent viscosity. 
The differences in viscosity due to the salts used in this study might be 
explained in terms of the effects of solutes on water. Bone (1973) stated 
that "When a solute is added to water, several things happen. First, the 
concentration of water is reduced, and second, the interaction of the solute 



37 



FIGURE 3. Illustration of the influence of salt type and level 
on viscosity of liquid yolk. 





10 




9 


^■N 


8 


CO 




Q_ 




C3 


7 


N-^ 


CM 


ft 


•"" 




x 






b< 


>- 




I— 




CO 


4 


C3 




C3 




CO 






3' 



■ s NaCI (No l 2 > 




38 
■ 


•=NaCI (l 2 > 




• 
• 
• 
• 
• 


*=KCI 




4h 


X= 07. SALT 


i 

• 

• 

• 

• 

• 


m 

M 

m 

M 

m 

m 

m 

§ 

m 

m 

m 

m 

a 

m 


• 
• 
• 
• 

.* 

/ 

• 


• 

• 

• 

• 

* 

• 

• 

• 

• 

• 

• 

• 

• 

• j 

• j 

m 
• * 

If / 

M 
M 
m 
M 

1 
/ / 

J / 

Jt / 
^^ / 
/ 

/ 


t 

/ 
/ 
/ 
/ 
/ 
/ 
/ 
/ 
/ 

* 


« ^ 







5 10 

SALT (%) 



s 



39 
with the water may break or increase the water structure." Ions which are 
smail and/or multivalent, such as Na , tend to have strong electric fields and 
are considered net structure formers (Fennema, 1976). Large and monovalent 
ions, including K , CI , and I , tend to disrupt the normal water structure 
and are termed net structure breakers (Fennema, 1976). The 3 salts tested in 
this experiment all provided CI" ions. The differences in yolk viscosity 
increases between the 3 salts, therefore, could be due to the Na + , K + , and I" 
ions. The addition of any of the salts would theoretically cause dehydration 
of the egg proteins. When the uniodized NaCl was used, the strong net 
structure forming ability of the Na + ion would compensate for the extra 
water split off by dehydration by binding with that water. With the loss of 
the water to the Na , the dehydrated proteins would be able to associate, 
and the large protein aggregate thus formed would then cause the increased 
viscosity. The difference between the uniodized and iodized NaCl could 
possibly be attributed to the I" ion. The iodized NaCl would provide 2 
structure breaking ions (Cl" and I"), which would result in less of the extra 
water being bound. Although the dehydrated proteins would still aggregate, 
the increased amount of unstructured water would result in less of a 
viscosity increase. Since both ions from the KC1 tend to be structure 
breakers, the extra water from the dehydrated proteins would be even less 
structured than with either of the NaCl salts, resulting in the lower viscosity 
increase. 

A noticeable change in yolk color occurred upon addition of any of the 
3 salts. Yolk containing either iodized or uniodized NaCl became dark 
yellow, while yolk containing KC1 became a deep yellow-orange color. This 
change in yolk color produced no noticeable difference in mayonnaise color. 



w 

Jordan and Whitlock (1955) and Jaax and Travnicek (1968) also reported a 
darkening in yolk color upon addition of NaCl. 

Emulsification capacity 

The effects of salt type and level on liquid yolk emulsification capacity 
are illustrated in Figure 4, while the corresponding treatment means are 
shown in Table 6 (Appendix). 

The emulsification capacity of the 0% salt sample was 11.25. This is 
comparable to the value of 11.10 + 0.39 reported by Young et al. (1983). The 
addition of any of the 3 salts at even the 5% level was found to dramatically 
reduce the emulsification capacity of the liquid yolk. 

Table 7 (Appendix) shows the treatment means for the effect of salt 
type on emulsification capacity of liquid yolk. No significant (P>0.05) 
differences in emulsification capacity between yolk treated with iodized 
NaCl and that treated with KC1 were found at* any of the 3 levels of salt 
addition. Uniodized NaCl caused a significant (P>0.05) decrease in 
emulsification capacity with a mean of 6.53. 

Table 8 (Appendix) shows the treatment means for the effect of salt 
level on emulsification capacity of liquid yolk. Salt level was found to have 
a significant (P>0.05) effect on emulsification capacity. The 5% level caused 
the least reduction in emulsification capacity, followed by the 10% level. 
The 15% level caused the greatest reduction in emulsificaton capacity. 

The emulsifying properties of egg yolk are due to the presence of 
protein and lipoprotein complexes (Sell et al., 1935). As suggested earlier, 
the addition of NaCl or KC1 probably caused a dehydration of those 
complexes, which in turn could influence their emulsifying properties. This 



»1 



FIGURE 4. Illustration of the influence of salt type and level 
on emulsification capacity of liquid yolk. 



42 



11 

llOi 

£ 

"5- 

l 4 ' 
eg 

S 2i 




X = 7. SALT 
■ = NaCI (No l 2 ) 

• = NaCI (l 2 ) 

* = KCI 



T 



■ r 

10 15 

SALT C/.) 



»3 

might account for the decrease in emulsification capacity of the liquid yolk 
upon the addition of the 3 salts. 

Mayonnaise tests 

The effects of salt type and level on apparent mayonnaise viscosity are 
illustrated in Figure 5, while the corresponding treatment means are shown 
in Table 9 (Appendix). The effects of salt type and level on mayonnaise 
spread are illustrated in Figure 6, with the corresponding treatment means 
being shown in Table 10 (Appendix). 

Analysis of the Brookfield viscometer data indicated that salt type had 
a significant (P>0.05) effect on apparent mayonnaise viscosity (Table 11, 
Appendix). Mayonnaise made with KC1 had the lowest apparent viscosity at 
each of the 3 levels, followed by mayonnaise made with uniodized NaCl. 
Mayonnaise made with iodized NaCl had the highest apparent viscosity at 
each of the 3 levels. 

Analysis of variance of the line spread data indicated that there was no 
significant (P>0.05) difference in spread between mayonnaise made with 
uniodized NaCl and that made with KC1 (Table 12, Appendix). Further 
analysis by Duncan's Multiple Range Test (Table 10, Appendix) showed that 
this was true only at the 5 and 15% levels. At the 10% level, Duncan's 
Multiple Range Test indicated that there was no significant (P>0.05) 
difference in spread between mayonnaise made with KCL and that made with 
iodized NaCl. 

Salt level had a significant (P>0.05) effect on both apparent viscosity 
and spread of mayonnaise (Tables 13 and 14, Appendix). Overall, mayonnaise 
with 10% salt had the highest mean Brookfield viscosity value, and the 



** 



FIGURE 5. Illustration of the influence of salt type and level 
on apparent mayonnaise viscosity. 



45 



50i 
45i 



^40i 

DO 

"35i 

CO 



30. 
25i 



CO 

S20« 
00 



15« 
Id 
5i 




„-*-' 



X = 0% SALT 
■ = NaCI (No l 2 ) 
•=NaC! (I 2 ) 
*=KCI 



,-'* 
^*~ 



T 



T 



10 

SALT <*) 



T 

15 



*6 



FIGURE 6. Illustration of the influence of salt type and level 
on mayonnaise spread. 



47 



10- 

&8i 
= 7i 

| 6 ' 

C051 

UJ 

2i 

1. 




X=0/. SALT 

■ = NaCI (No l 2 ) 

•=NaCI (l 2 ) 
*=KCI 



l 1 r 

5 10 15 

SALT (/.) 



48 
lowest mean spread; mayonnaise with 15% salt had an intermediate mean 
Brookfield viscosity value as well as an intermediate mean spread, and 
mayonnaise with 5* salt had the lowest mean Brookfield viscosity value and 
the highest mean spread. A general trend was observed with mayonnaise 
made with either KC1 or uniodized NaCl. As the level of either of those 
salts was increased from 5 to 15%, apparent viscosity of the mayonnaise 
increased. Iodized NaCl did not follow this trend however; the large increase 
in apparent viscosity which occurred in mayonnaise made with 10% iodized 
NaCl was followed by a decrease in apparent viscosity for mayonnaise made 
with 15% iodized NaCl. The reason for this increase/decrease is not known. 

The effects of salt type and level on mayonnaise stability are 
illustrated in Figure 7, while the corresponding treatment means are shown 
in Table 15 (Appendix). 

Both salt type and salt level were found to effect mayonnaise stability 
(Tables 16 and 17, Appendix). Overall, uniodized NaCl produced mayonnaise 
with the highest mean stability, followed by iodized NaCl. KC1 produced 
mayonnaise with the lowest mean stability. Mayonnaise containing 15% salt 
had the highest mean stability at 13.* days, followed by 10% salt at 7.9 
days, and 5% salt at 4.6 days. 

When the 3 salts were compared at each of the 3 levels, no significant 
(P>0.05) difference in stability was found at the 5% level for any of the 
salts. There was no significant (P>0.05) difference in stability between 
mayonnaise made with 10% uniodized NaCl and that made with 10% iodized 
NaCl, but mayonnaise made with 10% KC1 had a significantly (P>0.05) lower 
stability. At the 15% level, though, there was no significant (P>0.05) 
difference in stability of mayonnaise made with KC1 or iodized NaCl, but 



1*9 



FIGURE 7. Illustration of the influence of salt type and level 
on mayonnaise stability. 



GO 



15i 

14i 

13- 

12. 

11i 

10- 

9- 

8- 

7i 

6. 

5- 

4- 

3-X 
2- 



50 



/ t 




X = 0/. SALT 
■ = NaCI (No l 2 > 
• = NaCI (l 2 ) 
•=KCI 



■ r r 

5 10 15 

SALT (X.) 



51 
mayonnaise made with 15* uniodized NaCl had a significantly (P>0.05) higher 
stability. 

Krantz and Gordon (1928) found that NaCl stabilized some emulsions. In 
work conducted with emulsions stabilized by casein, Seifriz (1935) found that 
NaCl tended to stabilize oil-in-water emulsions, but had no influence on 
water-in-oil emulsions. Lowe (1955) suggested that the effect of NaCl on 
emulsion stability would probably depend on both the emulsifier and the 
concentration of the NaCl. Data from this study showed that addition of any 
of the salts at even the 5% level resulted in a significant (P>0.05) increase 
in stability over mayonnaise made with 0* salt. Lowe (1955) also found that 
salt (NaCl) increased mayonnaise stability. 

FROZEN YOLK 

Viscosity 

The effect of frozen storage time on salted yolk apparent viscosity is 
illustrated in Figure 8, while the corresponding treatment means are shown 
in Table 18 (Appendix). 

Storage of salted yolk at -10°C for even 24 hours (0 days) was found to 
result in a considerable increase in apparent viscosity over fresh salted yolk. 
Apparent viscosity of salted yolk stored 30 days was approximately three 
times greater than that stored 24 hours. There was no significant (P>0.05) 
difference, though, between yolk stored 30 and 60 days. Yolk stored at 
-10°C for 90 days had a significantly (P>0.05) higher apparent viscosity than 
any other treatment. Palmer et al. (1969a) also reported increases in 
viscosity of 10* salted yolk stored at -10°F over a period of 4 months. 
Powrie et al. (1963) suggested that viscosity changes in thawed yolk under 



52 



FIGURE 8. Illustration of the influence of frozen storage time 
on apparent viscosity of salted yolk. 



16- 

14- 

£12- 

SlO- 

% 8— 

»— 
55 2- 

| 1= 

M z 

.6- 



53 



X= LIQUID YOLK 



30 60 

DAYS FROZEN STORAGE 



T 
90 



54 
conditions of constant thawing rate were the result of protein structural 
alterations occurring in the frozen state of yolk. Davey et al. (1969) 
suggested that increased apparent viscosity of the lipovitellenin fraction 
after freezing was the basis for increased viscosity of frozen native yolk. 

Emulsification capacity 

The effect of frozen storage time on emulsification capacity of salted 
yolk is illustrated in Figure 9, with the corresponding treatment means being 
shown in Table 19 (Appendix). 

Storage of salted yolk at -10°C for 2* hours (0 days) resulted in a 
reduction in emulsification capacity to 6.39 from 6.85 for fresh liquid yolk 
with 10% iodized NaCl. Storage at -10°C for 60 days reduced the 
emulsification capacity to 6.10, which was not significantly (P>0.05) 
different from the emulsification capacity of 6.06 for yolk stored 90 days. 
Thirty days of frozen storage resulted in yolk with the lowest emulsification 
capacity at 5.92, but this was not significantly (P>0.05) different from yolk 
stored 90 days. Freezing of biological materials such as egg yolk results in 
pure water being removed to form ice crystals (Meryman, 1956). This causes 
dehydration of the proteins, and an increase in the concentration of salts 
(Powrie et al., 1963). Powrie et al. (1963) further suggested that the 
consequent changes in water structure due to dehydration and salt 
concentration increase could allow for rearrangement and aggregation of the 
yolk lipoproteins. This rearrangement and aggregation could influence the 
emulsification capacity of the yolk. The reason why emulsification capacity 
decreased during the first 30 days of frozen storage, increased during the 



55 



FIGURE 9. Illustration of the influence of frozen storage time 
on emulsification capacity of salted yolk. 



56 



X=LIQUID YOLK 



^81 



7i 



s» 



S5i 

I 4 ' 

o 



30 60 90 
DAYS FROZEN STORAGE 



57 
second 30 days, and then decreased slightly during the last 30 days of frozen 
storage, though, is unclear. 

Mayonnaise tests 

The effect of frozen storage time on apparent mayonnaise viscosity is 
illustrated in Figure 10, while the corresponding treatment means are shown 
in Table 20 (Appendix). The effect of frozen storage time on mayonnaise 
spread is illustrated in Figure 11, with the corresponding treatment means 
being shown in Table 21 (Appendix). 

Mayonnaise made from yolk stored at -10°C for 60 days had a 
significantly (P>0.05) higher apparent viscosity than that made from any 
other frozen yolk sample. No significant (P>0.05) difference in apparent 
viscosity was found between mayonnaise made from yolk stored 0, 30, or 90 
days. Line spread data showed that yolk stored 60 days produced mayonnaise 
with a significantly (P>0.05) lower spread than any other sample. No 
significant (P>0.05) difference in spread was found between mayonnaise made 
from yolk stored 0, 30, or 90 days. Both apparent viscosity and spread of 
mayonnaise made from 60 day frozen yolk were comparable to the apparent 
viscosity and spread of mayonnaise made from fresh liquid yolk containing 
10% iodized NaCl. 

The effect of frozen storage time on stability of mayonnaise is 
illustrated in Figure 12, while the corresponding treatment means are shown 
in Table 22 (Appendix). 

Storage of yolk at -10°C for 2* hours resulted in a mean stability of 22 
days. This is a dramatic increase over the 8.3 days determined for fresh 
liquid salted yolk. Subsequent storage of yolk at -10°C for 30, 60, and 90 



58 



FIGURE 10. Illustration of the influence of frozen storage time 
on apparent mayonnaise viscosity. 



59 







X= LIQUID YOLK 








£60- 
cT50- 


X 






x40- 








£30- 

co 

S20- 














10- 






















1 







30 60 
DAYS FROZEN STORAGE 



90 



60 



FIGURE 11. Illustration of the influence of frozen storage time 
on mayonnaise spread. 



61 



~6. 

CO 



X= LIQUID YOLK 



in 

W 

S2H 



CO 



1l 



30 60 
DAYS FROZEN STORAGE 



T 

90 



62 



FIGURE 12. Illustration of the influence of frozen storage time 
on mayonnaise stability. 



63 



CO 



24« 
21- 
,18- 
" 15—1 
: 12. 

94 

6. 



X= LIQUID YOLK 



I 

30 60 

DAYS FROZEN STORAGE 



90 



64 
days produced mayonnaise with mean stabilities of 21, 20, and 21 days 
respectively. 

YOLK SOLIDS 

Viscosity 

Apparent viscosity of the 3 types of yolk solids is illustrated in Figure 
13, with the corresponding treatment means being shown in Table 23 
(Appendix). 

All 3 types of yolk solids were found to have a dramatically higher 
apparent viscosity than either liquid or frozen yolk. There was a significant 
(P>0.05) difference in apparent viscosity between all 3 types of yolk solids; 
free flow yolk solids had the highest apparent viscosity at 627,200 c.p.s., 
followed by plain yolk solids at 501,200 c.p.s. Low viscosity yolk solids had 
the lowest apparent viscosity at 172,400 c.p.s. Varadarajulu and Cunningham 
(1972) also found that spray dried yolk had a greater apparent viscosity than 
fresh yolk. 

Em unification capacity 

Emulsification capacity for the 3 types of yolk solids is illustrated in 
Figure 1*, while the corresponding treatment means are shown in Table 24 
(Appendix). 

All 3 types of yolk solids had a considerably lower emulsification 
capacity than fresh yolk containing 10* iodized NaCl. No significant (P>0.05) 
difference was found in emulsification capacity between plain yolk solids and 
free flow yolk solids. Low viscosity yolk solids had a significantly (P>0.05) 
lower emulsification capacity at 6.02. These results agree with those of 



65 



FIGURE 13. Illustration of the apparent viscosity of the 3 types 

of yolk solids. 

X = liquid yolk, P = plain yolk solids, 

F = free flow yolk solids, L = low viscosity yolk solids. 






66 




i r 

SOLIDS TYPE 



L 



67 



FIGURE 14. Illustration of the emulsification capacity of the 
3 types of yolk solids. 



68 



SB 



9 

8 

57 

CJ 

§4- 

CO 

= 2. 

CO 

—J 

1 1- 



X= LIQUID YOLK 

P = PLAIN YOLK SOLIDS 

F = FREE FLOW YOLK SOLIDS 

L=L0W VISCOSITY YOLK SOLIDS 



T 

P F 

SOLIDS TYPE 






69 
Rolfes et al. (1955), who found that lyophilization impaired yolk emulsifying 
properties, and Zabik (1969) and Varadarajulu and Cunningham (1972), who 
found that spray drying altered the emulsifying properties of the yolk. 
Schultz et al. (1966) reported that a rapid increase in extractability of "free 
lipids" during drying was extremely detrimental to the emulsifying function 
of the yolk. 

Mayonnaise tests 

Apparent viscosity of mayonnaise made from each of the 3 types of 
yolk solids is illustrated in Figure 15, with the corresponding treatment 
means being shown in Table 25 (Appendix). Spread of mayonnaise made from 
each of the 3 types of yolk solids is illustrated in Figure 16, while the 
corresponding treatment means are shown in Table 26 (Appendix). Apparent 
viscosity was significantly (P>0.05) different for mayonnaise made from each 
yolk sample; mayonnaise made from low viscosity solids had the highest 
apparent viscosity at 38,250 c.p.s., followed by plain yolk solids mayonnaise 
at 29,500 c.p.s., and free flow yolk solids mayonnaise at 23,000 c.p.s. No 
significant (P>0.05) difference in spread was found between mayonnaise made 
from any of the yolk solids samples. 

Observation during the initial stage of mayonnaise formation indicated 
that yolk solids did not foam as much as either liquid or frozen yolk. These 
observations agree with the results of Schultz et al. (1966), who reported 
that egg yolk which is dried and subsequently rehydrated loses it's foaming 
ability. Mayonnaise made from yolk solids was also darker yellow in color 
and had less volume than that made from either liquid or frozen yolk. 



70 



FIGURE 15. Illustration of the apparent viscosity of mayonnaise 
made from the 3 types of yolk solids. 



71 



^50 
eo 

eo 

«40- 



|35. 

5230- 



25. 



20- 



X= LIQUID YOLK 

P = PLAIN YOLK SOLIDS 

F = FREE FLOW YOLK SOLIDS 

Lb LOW VISCOSITY YOLK SOLIDS 



T 



■ ■ 

P F 

SOLIDS TYPE 



72 



FIGURE 16. Illustration of the spread of mayonnaise made from the 
3 types of yolk solids. 



73 



1^ 


X= LIQUID YOLK 






t=6- 


P = PLAIN YOLK SOLIDS 
F=FREE FLOW YOLK SOLIDS 


= 


L = L0W VISCOSITY YOLK SOLIDS 


2=5- 

s 




^4" 


X ^ 


CO 

UJ 

£2- 

CO 










1" 














r 


i 


r 



P F 

SOLIDS TYPE 



74 
Stability values for mayonnaise made from the 3 types of yolk solids are 
illustrated in Figure 17, while the corresponding treatment means are shown 
in Table 27 (Appendix). 

Mayonnaise made from free flow yolk solids had the highest stability at 
12 days. Mayonnaise made from plain yolk solids and from low viscosity yolk 
solids had stabilities of 10 days. These values are approximately intermediate 
between stability values determined for mayonnaise made from frozen yolk 
(highest overall stability) and liquid yolk (lowest overall stability). 

MAYONNAISE MICROBIOLOGY 

Microbial counts before and after incubation for all mayonnaise samples 
are shown in Table 28. 

Standard plate counts before and after incubation of mayonnaise made 
from either the liquid or frozen samples resulted in a general trend - except 
for the 15% iodized NaCl, the number of colony forming units was less after 
incubation than before. This is probably attributable to the combination of 
heat, acid, and salt present during incubation. Standard plate counts on 
mayonnaise made from yolk solids showed an increase in the number of 
colony forming units after incubation. Differences in mold and yeast counts 
before and after incubation were relatively slight for all mayonnaise samples. 



75 



FIGURE 17. Illustration of the stability of mayonnaise made from the 
3 types of yolk solids. 









76 



35. 
30- 

£20- 



CO 



15- 
10- 

5- 



X = LIQUID YOLK 

0= FROZEN YOLK 

P = PLAIN YOLK SOLIDS 

F = FREE FLOW YOLK SOLIDS 

L = LOW VISCOSITY YOLK SOLIDS 



P F 

SOLIDS TYPE 



77 
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78 
Corran, 3. W. 19*3. Some observations on a typical food emulsion. In 

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79 
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80 
King, A. 1941. Some factors governing the stability of oil-in-water emulsions. 

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81 
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82 
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83 
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Tech. 23:130-132. 



u 



APPENDIX 



85 
TABLE 3. Treatment Means for Egg Yolk Viscosity 



1 2 
Treatment Mean ' 



(c.p.s.) 



15% uniodized NaCl 1008.0" 

15* iodized NaCl 932.0 b 

15* KC1 560.0 C 

1056 uniodized NaCl 500 .0 C 

10* iodized NaCl 288.0 e 

10* KC1 216.0 f 

5* uniodized NaCl 208.0 f 

5% iodized NaCl 168.0 g 

5% KC1 120.0 h 

0* salt 104.0 1 



Means with the same letter are not significantly different. 



2 

Means calculated from 5 replications. 



86 



TABLE *. Treatment Means for Effect of Salt Type 
on Apparent Yolk Viscosity 



Treatment Mean 



(c.p.s.) 



Uniodized NaCl 572.0" 

Iodized NaCl 462.7 b 

KC1 298.7 C 



Means with the same letter are not significantly different. 



TABLE 5. Treatment Means for Effect of Salt Level 
on Apparent Yolk Viscosity 



Treatment Mean 



(c.p.s.) 



15% 833.3" 

10% 33*.7 b 

5% 165.3 C 



Means with the same letter are not significantly different. 



87 
TABLE 6. Treatment Means for Emulsification Capacity 



I 2 
Treatment Mean ' 



(ml oil/g yolk) 



0% salt 11.25" 

5* iodized NaCl 7.27 b 

5% KC1 7.22 b 

5% uniodized NaCl 6.92 c 

10* iodized NaCl 6.85 c 

10% KC1 6.81 c ' d 

15% iodized NaCl 6.63 d ' e 

15% KC1 6.52 e ' f 

10% uniodized NaCl 6.39 f,g 

15% uniodized NaCl 6.27 g 



Means with the same letter are not significantly different. 
Means calculated from 5 replications. 



TABLE 7. Treatment Means for Effect of Salt Type 
on Emulsification Capacity 



Treatment Mean 



(ml oil/g yolk) 



Iodized NaCl 6.92 

KC1 6.85 a 

Uniodized NaCl 6.53 b 



Means with the same letter are not significantly different. 



TABLE 8. Treatment Means for Effect of Salt Level 
on Emulsification Capacity 



Treatment Mean 



(ml oil/g yolk) 



5% 7.1» a 

10* 6.68 b 

15% 6.48 c 



Means with the same letter are not significantly different. 



89 

TABLE 9. Treatment Means for Apparent Mayonnaise Viscosity 



1 2 
Treatment Mean ' 



(c.p.s.) 



10* iodized NaCl 49,250.0 

15* iodized NaCl 34,750.0 b 

5* iodized NaCl 29,000.0 C 

15* uniodized NaCl 27,250.0 c ' d 

10% uniodized NaCl 26,000.0 d,e 

15* KC1 24,750.0 e 

10* KC1 20,750.0 f 

5* uniodized NaCl 20,000.0 f 

5* KC1 17,250.0 g 

0* salt 10,000.0 h 



Means with the same letter are not significantly different. 
Means calculated from 4 readings. 



90 
TABLE 10. Treatment Means for Mayonnaise Spread 



Treatment Mean 1 ' 2 

(spread units) 



0% salt 10. a 

5% KC1 7.3 b 

5* uniodized NaCl 6.8 C 

15% KC1 5.4 d 

5% iodized NaCl 5.3 d 

10% uniodized NaCl 5.3 d 

15% uniodized NaCl 5.0 d ' e 

15% iodized NaCl *.9 d,e 

10% KC1 *.5 e ' f 

10% iodized NaCl 4.0 f 



Means with the same letter are not significantly different. 
Means calculated from * readings. 



91 



TABLE 11. Treatment Means for Effect of Salt Type 
on Apparent Mayonnaise Viscosity 



Treatment Mean 



(c.p.s.) 



Iodized NaCl 37,667 .0 a 

Uniodized NaCl 2«,*17.0 b 

KC1 20,917.0° 



Means with the same letter are not significantly different. 



TABLE 12. Treatment Means for Effect of Salt Type 
on Mayonnaise Spread 



Treatment Mean 



(spread units) 



KC1 5.7 a 

Uniodized NaCl 5.7 a 

Iodized NaCl *.7 b 



Means with the same letter are not significantly different. 



92 

TABLE 13. Treatment Means for Effect of Salt Level 
on Apparent Mayonnaise Viscosity 



Treatment Mean 



(c.p.s.) 



10% 32,000.0 a 

15* 28,917.0 b 

5% 22,083.0 C 



Means with the same letter are not significantly different. 



TABLE 1*. Treatment Means for Effect of Salt Level 
on Mayonnaise Spread 



Treatment Mean 



(spread units) 



5* 6.4 a 

15% 5.1 b 



10% 



Means with the same letter are not significantly different. 



93 
TABLE 15. Treatment Means for Mayonnaise Stability 



Treatment Mean ' 



(days at 40 °C) 



15% uniodized NaCi 15.CT 

15* KC1 13.0 b 

15% iodized NaCl 12.3 b 

10% iodized NaCl 8.3 C 

10% uniodized NaCl 8.3 C 

10% KC1 7.0 d 

5% iodized NaCl 5.0 e 

5% uniodized NaCl 4.3 e 

5% KC1 4.3 e 

0% salt 3.0 f 



Means with the same letter are not significantly different. 



Means calculated from 3 replications. 



9* 
TABLE 16. Treatment Means for Effect of Salt Type 
on Mayonnaise Stability 



Treatment Mean 

(days at 40 °C) 



Uniodized NaCl 9.2 

Iodized NaCl 8.6 

KC1 8.1 



TABLE 17. Treatment Means for Effect of Salt Level 
on Mayonnaise Stability 



Treatment Mean 

(days at 40 °C) 



15* 13.4 

10% 7.9 

5% 4.6 



95 

TABLE 18. Treatment Means for Apparent Egg Yolk Viscosity 



1 2 
Treatment Mean ' 



(c.p.s.) 



90 days frozen storage 14,800.0 a 

30 days frozen storage 2,080.0 

60 days frozen storage 2,000.0 

days frozen storage 68*.0 C 

Liquid yolk (10% iodized NaCl) 288.0 



Means with the same letter are not significantly different. 
Means calculated from 5 replications. 



96 
TABLE 19. Treatment Means for Emulsification Capacity 



1 2 
Treatment Mean ' 



(ml oil/g yolk) 



Liquid yolk (10% iodized NaCl) 6.85 

days frozen storage 6.39 

60 days frozen storage 6.10 

90 days frozen storage 6.06 ' c 

30 days frozen storage 5.92 c 



Means with the same letter are not significantly different. 

2 

Means calculated from 5 replications. 



97 
TABLE 20. Treatment Means for Apparent Mayonnaise Viscosity 



1 2 
Treatment Mean ' 



(c.p.s.) 



60 days frozen storage 50,250.0 a 

Liquid yoJk (10% iodized NaCl) *9,250.0 

90 days frozen storage 36,000.0 

days frozen storage 33,750.0 

30 days frozen storage 31,250.0 



Means with the same letter are not significantly different. 



Means calculated from 4 readings. 



98 

TABLE 21. Treatment Means for Mayonnaise Spread 



Treatment Mean ' 



(spread units) 



30 days frozen storage 4.3 

days frozen storage 4.3 

Liquid yolk (10% iodized NaCl) 4.0 

90 days frozen storage 3.9 a 

60 days frozen storage 3.0 



Means with the same letter are not significantly different. 



Means calculated from 4 readings. 



99 

TABLE 22. Treatment Means for Mayonnaise Stability 



Treatment Mean 

(days at 40 °C) 



days frozen storage 22 

30 days frozen storage 21 

90 days frozen storage 21 

60 days frozen storage 20 
Liquid yolk (10* iodized NaCl) 8.3 



100 
TABLE 23. Treatment Means for Apparent Egg Yolk Viscosity 



Treatment Mean ' 



(c.p.s.) 



Free flow yolk solids 627,200.0 a 

Plain yolk solids 501,200.0 b 

Low viscosity yolk solids 172,*00.0 C 
Liquid yolk (10% iodized NaCl) 288.0 



Means with the same letter are not significantly different. 



Means calculated from 5 replications. 



101 
TABLE 24. Treatment Means for Emulsification Capacity 



1 2 
Treatment Mean ' 

(ml oil/g yolk) 



Liquid yolk (10% iodized NaCl) 6.85 

Plain yolk solids 6.33 a 

Free flow yolk solids 6.32 a 

Low viscosity yolk solids 6.02 



Means with the same letter are not significantly different. 
Means calculated from 5 replications. 



102 
TABLE 25. Treatment Means for Apparent Mayonnaise Viscosity 



Treatment Mean ' 

(c.p.s.) 



Liquid yolk (10% iodized NaCl) 49,250.0 

Low viscosity yolk solids 38,250.0 a 

Plain yolk solids 28,500.0 b 

Free flow yolk solids 23,000.0° 



Means with the same letter are not significantly different. 

2 
Means calculated from * readings. 



103 

TABLE 26. Treatment Means for Mayonnaise Spread 



Treatment Mean 1 ' 2 

(spread units) 



Liquid yolk (10% iodized NaCl) 4.0 

Low viscosity yolk solids 3.9 a 

Plain yolk solids 3.3 a 

Free flow yolk solids 3.3 a 



Means with the same letter are not significantly different. 



2 

Means calculated from 4 readings. 



10* 
TABLE 27. Treatment Means for Mayonnaise Stability 



Treatment Mean 

(days at *0°C) 



Frozen yolk (average) 21 

Free flow yolk solids 12 

Plain yolk solids 10 

Low viscosity yolk solids 10 

Liquid yolk (10* iodized NaCl) 8.3 






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105 



ACKNOWLEDGEMENTS 

Sincere appreciation is expressed to my major professor, Dr. F. E. 
Cunningham, for his guidance, patience, interest, and understanding 
throughout this research project. 

Appreciation is also expressed to Dr. D. Y. C. Fung and Dr. R. Carl 
Hoseney for not only serving on my committee, but for their interest and 
advice, which was always helpful. 

Special thanks is extended to Dr. Ken Kemp, Department of Statistics, 
for his help with the statistical analysis, and to Dr. Len Harbers for his time 
and effort in putting together my slides. 

Finally, my love and appreciation is extended to my parents, whose 
support and encouragement have made the effort worthwhile. 



PROPERTIES OF SEVERAL TYPES OF SALTED YOLK 
AND FUNCTIONALITY IN MAYONNAISE 



by 

L. J. Harrison 
B.S., Texas Tech University, Lubbock, Texas, 1982 

AN ABSTRACT OF A MASTER'S THESIS 

submitted in partial fulfillment of the 
requirements for the degree 

MASTER OF SCIENCE 

Food Science 

(Department of Animal Sciences and Industry) 

KANSAS STATE UNIVERSITY 

Manhattan, Kansas 

1984 



ABSTRACT 

Viscosity, em unification capacity, and functionality in mayonnaise of 
several types of salted yolk were studied. 

The effects of salt type and level on the yolk properties were 
determined in the liquid yolk study. The addition of iodized NaCl, uniodized 
NaCl, or KC1 resulted in an increase in yolk viscosity and a decrease in 
emulsification capacity. Viscosity of yolk increased as salt level increased 
from 5 to 15%, while emulsification capacity decreased as salt level 
increased. Mayonnaise made from liquid yolk containing any of the 3 salts 
had a higher apparent viscosity, lower spread, and higher stability than that 
made from liquid yolk with 0% salt. 

Frozen storage of yolk containing 10% iodized NaCl for 0, 30, 60, and 
90 days resulted in increased apparent yolk viscosity and decreased 
emulsification capacity. Mayonnaise made from yolk stored 60 days had a 
higher apparent viscosity and a lower spread than that made from any other 
frozen yolk sample. Mayonnaise made from all frozen yolk samples had 
stability values of greater than or equal to 20 days. 

Plain, free flow, and low viscosity yolk solids had higher apparent 
viscosities, and lower emulsification capacities than liquid yolk. All 3 types 
of yolk solids produced mayonnaise with lower viscosities and lower spreads 
than that made from liquid yolk. Stability values for mayonnaise made from 
the 3 types of yolk solids were intermediate between those for mayonnaise 
made from liquid yolk (lowest overall stability) and that made from frozen 
yolk (highest overall stability).